Unix is one of the IT world's few living legends. It has been in continuous use since its birth in 1969, and its storied past is like that of a nation: Inept rulers brought it to the brink of ruin, a dictator was deposed by a public rebellion, coalitions were made and dissolved, party loyalists inflamed passions by defecting to the other side and, for a time, anarchy reigned. For corporations, Unix's journey through adolescence was anything but fun.

Corporate users rode out Unix's growing pains, in part by ignoring vendor pleas to install every new OS upgrade. Unix is no fire-and-forget endeavor. It takes months to tweak out a Unix server for optimal performance and stability. But once you find that elusive combination of hardware, OS version, and patches, you leave it alone. Unix has endured because, when it is tuned, a Unix box is a magnificent beast. It seems able to shoulder any load, and it'll run and run until something melts.

Many believe that Linux hurt commercial Unix by doing for free what expensive operating systems had done for years. That's sadly true for SCO and SGI, but IBM, Sun Microsystems, and Hewlett-Packard have thrived in the Unix renaissance brought about by Linux. Using Linux as a teaching tool, universities are once again graduating Unix-literate administrators and developers. Linux knowledge isn't directly applicable to enterprise Unix systems, but Linux experience creates a solid foundation for enterprise training as well as an understanding of why Linux has not replaced Unix. Commercial Unix development, particularly bug fixes and enhancements, is spurred ahead by the knowledge that an entire product line, even an entire company, rides on the OS.

Our snapshots look at six commercial Unix variants, giving you an idea of where each is and where each is headed. We looked at how well the variants work with a set of 10 corporate applications: Oracle 8i database, IBM WebSphere Application Server, Adobe FrameMaker 6, iPlanet Enterprise Web Server, Microsoft Internet Explorer, Sybase ASE, Lotus Domino, ChiliSoft ASP, Vitria BusinessWare, and SAP. The application score shows how many of the sets each OS supports.

Finally, we gave each an overall score to illustrate how healthy each is for work in the enterprise. The score depicts each variant's outlook, based on the pace of new development, software portability, quality of documentation and support, and market position.

Prognosis: SGI can't win. The company tried to distance itself from sluggish MIPS processors and its quirky Irix OS by shifting toward Intel PCs, Windows, and Linux. That brought cries of abandonment from SGI's existing Irix customers, forcing the company to promise new Irix platforms through 2006.

SGI has a rare gift for building ultrafast server I/O subsystems. That serves SGI's data-intensive traditional markets (film and TV animation, medical and scientific visualization, and high-end digital media) well, but that niche is too small to sustain SGI.

The way we see it, there's no real hope: Irix is a goner. Hopefully, its user base will support future servers based on Linux and other operating systems. If not, we hope Irix doesn't take SGI down with it.

Disadvantages: IBM's manuals and support documents are often inscrutable; plans for enterprise IA-64 and Linux systems raise concerns that IBM may scale back RS/6000 and AIX.

Prognosis: AIX 5L, code-named Project Monterey, borrows pieces from several Unix implementations to create a versatile, broadly compatible operating environment. IBM is hedging its bets, blessing Linux as its platform-unifying OS and promising to build AIX for Intel's 64-bit CPU architecture. That has raised doubts about IBM's commitment to AIX and RS/6000, but AIX users shouldn't fret. It'll be a long time before Linux or Intel can measure up to IBM's current enterprise Unix offerings.

IBM has always taken on lots of partners, but IBM rarely alters its strategy to please them. Therefore, we believe AIX is here to stay, and we're glad IBM is offering users an alternative to AIX on what has been a locked-down platform.

Compaq Tru64 Unix

Current release: Tru64 Unix 5.1

Platform: Compaq Alpha workstations and servers

Standard: Unix 95

Application score: 4 out of 10

Advantages: Tru64 uses the powerful, lightweight Carnegie-Mellon Mach kernel; the 64-bit Alpha CPU is the best available for small and midsize servers; this continues Digital Equipment's legacy of creating powerful, affordable server systems.

Disadvantages: Compaq lacks experience and credibility outside the Intel server market; Linux is very popular among Alpha users; and holes in System V compatibility make application porting difficult.

Prognosis: Of the many gems acquired in Compaq's purchase of Digital Equipment, few shine as brightly as the Alpha CPU. Alpha routinely tops SPEC (Standard Performance Evaluation Corporation) benchmarks as the fastest CPU at a given clock speed.

Compaq changed Digital Unix's name to Tru64 Unix to highlight the Alpha chip's 64-bit pedigree. Now Compaq has to earn the trust of the large-scale server market.

Unfortunately, Compaq's PC credentials do it more harm than good. Likewise, Linux and the mature OpenVMS may win more enterprise accounts than the fairly proprietary Tru64. Intel will undoubtedly pressure Compaq to prefer IA-64 chips over Alpha.

Tru64 Unix on Alpha leads the pack in raw performance, but we suggest you wait to see what Compaq does with Alpha after IA-64 debuts.

Disadvantages: HP PA-RISC architecture is falling behind in performance relative to the competition.

Prognosis: Hewlett-Packard is the Volvo of IT: It quietly churns out ugly, bulletproof boxes that virtually care for themselves. HP is rarely first or fastest, but it packs enormous value into its Unix products.

Not surprisingly, HP-UX is almost Linux-like in its completeness, with time-proven enterprise tools and services included in the bundle.

HP's inclusion of the Veritas journaling file system moves HP-UX 11i to the front of the pack.

Once HP catches up to rivals' performance and certifies HP-UX as Unix 98-compliant, it could move ahead of Sun and IBM.

SCO UnixWare

Current release: UnixWare 7.1

Platform: Intel PC workstations and servers

Standard: Unix 95

Application score: 0 out of 10

Advantages: SCO is the owner of Unix System V source code; UnixWare is the most powerful and complete PC Unix; and it ships with excellent, affordable development tools.

Disadvantages: Development has been stagnant lately; sales have been trounced by free Linux and $75 Solaris x86; and most importantly, UnixWare does not support high-profile back-office applications.

Prognosis: The Santa Cruz Operation holds the keys to the kingdom: the source code for System V Unix. As such, UnixWare 7.1 is as pure a Unix as you'll find, and SCO surrounds it with a healthy assortment of tools and services.

Nevertheless, that hasn't done SCO much good. PC Unix has always been a tough sell except in limited vertical markets. When Linux got respectable and Sun slashed the price of Solaris x86 to $75, SCO was shoved out of the market it created.

Advantages: Brilliant, aggressive marketing made Solaris the de facto Unix; the Sparc and Intel versions are the same OS; and Solaris has the broadest application support of any commercial Unix-based OS.

Prognosis: Tough marketing and driven development catapulted Sun to first place, a position Sun jealously protects. Simply, Solaris leads because Sun makes sure that everything runs on Solaris.

Price and performance combine to form Sun's Achilles' heel and the door through which IBM and HP gain access to corporate accounts. Sun customers benefit from a huge and well-trained workforce, Sun's crack consulting staff, and Sun's quick resolution of Solaris bugs. Those advantages, along with Sun's ownership of Java and its involvement in iPlanet, make Sun the safest choice in enterprise Unix systems.

This story, "Six Unix OS flavors run the gamut" was originally published by
InfoWorld.